commit 56b5ad31cdf0a1e9f76a5f864a60e114da1c73be
Author: Märt Kalmo <mart.kalmo@gmail.com>
Date:   Wed May 3 15:17:25 2017 +0300

    starting state

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7072bbc
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,9 @@
+node_modules
+
+/.settings
+/.classpath
+/.project
+
+/.idea
+*.iml
+*.log
diff --git a/dao.js b/dao.js
new file mode 100644
index 0000000..1d406dd
--- /dev/null
+++ b/dao.js
@@ -0,0 +1,25 @@
+'use strict';
+
+const mongodb = require('mongodb');
+const ObjectID = require('mongodb').ObjectID;
+const COLLECTION = 'test-collection';
+
+class Dao {
+
+    connect(url) {
+        return mongodb.MongoClient.connect(url)
+            .then(db => this.db = db);
+    }
+
+    findAll() {
+        return this.db.collection(COLLECTION).find().toArray();
+    }
+
+    close() {
+        if (this.db) {
+            this.db.close();
+        }
+    }
+}
+
+module.exports = Dao;
diff --git a/executor.js b/executor.js
new file mode 100644
index 0000000..1bfa709
--- /dev/null
+++ b/executor.js
@@ -0,0 +1,13 @@
+
+// 1
+var promise = sqrt(4);
+
+promise.then(result => console.log(result))
+       .catch(error => console.log('Error: ' + error));
+
+function sqrt(arg) {
+    console.log('calculate sqrt(' + arg + ')');
+    return parseInt(arg) >= 0
+        ? Promise.resolve(Math.sqrt(arg))
+        : Promise.reject('bad argument');
+}
diff --git a/exercises.js b/exercises.js
new file mode 100644
index 0000000..55bb564
--- /dev/null
+++ b/exercises.js
@@ -0,0 +1,63 @@
+
+// 1
+var promise = sqrt(4);
+
+// 2
+var promise = sqrt(-1);
+
+// 3
+var promise = sqrt(9)
+    .then(result => {
+        return result + 1;
+    });
+
+// 4
+var promise = sqrt(9)
+    .then(result => result + 1)
+    .then(result => result + 2);
+
+// 5
+var promise = sqrt(16)
+    .then(result => {
+        return sqrt(result);
+    });
+
+// 6
+var promise = sqrt(16)
+    .then(result => sqrt(result))
+    .then(result => result + 1);
+
+// 7
+var promise = sqrt(4)
+    .then(result => {
+        console.log(result);
+    });
+
+// 8
+var promise = sqrt(4)
+    .then(result => {
+        throw 'hello';
+    })
+    .then(result => console.log(result));
+
+// 9
+var promise = sqrt(4)
+    .then(() => Math.hello())
+    .then(result => console.log(result));
+
+// 10
+var promise = sqrt(4)
+    .then(() => {
+        throw 'error'
+    }).catch(error => {
+        console.log('logging: ' + error);
+    });
+
+// 11
+var promise = sqrt(4)
+    .then(() => {
+        throw 'error'
+    }).catch(error => {
+        console.log('logging: ' + error);
+        throw error;
+    });
diff --git a/mongo.js b/mongo.js
new file mode 100644
index 0000000..cf51e6a
--- /dev/null
+++ b/mongo.js
@@ -0,0 +1,26 @@
+'use strict';
+
+const mongodb = require('mongodb');
+const Dao = require('./dao.js');
+const ObjectID = mongodb.ObjectID;
+
+var url = 'mongodb://...';
+
+var data = { name: 'Jill' };
+
+var database;
+mongodb.MongoClient.connect(url).then(db => {
+    database = db;
+    return db.collection('test-collection').insertOne(data);
+}).then(() => {
+    closeDb(database)
+}).catch(error => {
+    closeDb(database);
+    throw error;
+});
+
+function closeDb(database) {
+    if (database) {
+        database.close();
+    }
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..1ec38f6
--- /dev/null
+++ b/package.json
@@ -0,0 +1,7 @@
+{
+  "name": "exmongo",
+  "version": "1.0.0",
+  "devDependencies": {
+    "mongodb": "^2.2.25"
+  }
+}